Enfortumab Vedotin and Pembrolizumab in Cisplatin-Eligible Bladder Cancer

Neoadjuvant cisplatin-based chemotherapy is a standard therapy for muscle-invasive bladder cancer. The efficacy and safety of neoadjuvant and adjuvant (perioperative) enfortumab vedotin-pembrolizumab as compared with neoadjuvant cisplatin-based chemotherapy in persons with this cancer are unclear.

We conducted a phase 3, open-label, randomized trial involving adults with muscle-invasive bladder cancer eligible for cisplatin-based chemotherapy and radical cystectomy with pelvic lymph-node dissection (cystectomy). Participants were assigned to receive neoadjuvant enfortumab vedotin-pembrolizumab (4 cycles; enfortumab vedotin [1.25 mg per kilogram of body weight on days 1 and 8] and pembrolizumab [200 mg on day 1] every 3 weeks), cystectomy, and 5 cycles of enfortumab vedotin and 13 cycles of pembrolizumab as adjuvant therapy or to receive neoadjuvant cisplatin-gemcitabine (4 cycles; cisplatin [70 mg per square meter of body-surface area on day 1] plus gemcitabine [1000 mg per square meter on days 1 and 8] every 3 weeks) and cystectomy. The primary end point was event-free survival; key secondary end points were overall survival and pathological complete response. Safety was assessed.

A total of 405 participants were assigned to receive enfortumab vedotin-pembrolizumab and 403 to receive cisplatin-gemcitabine. The median time from randomization to the data-cutoff date was 33.6 months (range, 22.5 to 53.6). A total of 86.7% of the participants in the enfortumab vedotin-pembrolizumab group and 89.6% of those in the cisplatin-gemcitabine group underwent cystectomy. At 2 years, estimated event-free survival was 79.4% with enfortumab vedotin-pembrolizumab and 66.2% with cisplatin-gemcitabine (hazard ratio for an event or death, 0.53; 95% confidence interval [CI], 0.41 to 0.70; P<0.001); estimated overall survival was 86.9% and 81.3%, respectively (hazard ratio for death, 0.65; 95% CI, 0.48 to 0.89; two-sided P = 0.006). A pathological complete response occurred in 55.8% and 32.5% of the participants (P<0.001). The incidence of grade 3 or higher adverse events of any cause was 75.7% with enfortumab vedotin-pembrolizumab and 67.2% with cisplatin-gemcitabine.

Among participants with muscle-invasive bladder cancer eligible for cisplatin-based chemotherapy, perioperative enfortumab vedotin-pembrolizumab led to significantly better event-free and overall survival outcomes and a significantly higher incidence of pathological complete response than neoadjuvant cisplatin-gemcitabine, but with more adverse events of grade 3 or higher. (Funded by Merck Sharp and Dohme and others; KEYNOTE-B15/EV-304 ClinicalTrials.gov number, NCT04700124.).